Graduate Institute of Mind, Brain and Consciousness (GIMBC), Taipei Medical University, Taipei, Taiwan.
Graduate Institute of Mind, Brain and Consciousness (GIMBC), Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Center (BCRC), TMU-Shuang Ho Hospital, New Taipei City, Taiwan.
Cortex. 2023 Oct;167:41-50. doi: 10.1016/j.cortex.2023.05.022. Epub 2023 Jul 12.
Neuroimaging and lesion studies suggested that the dorsolateral prefrontal and posterior parietal cortices mediate visual metacognitive awareness. The causal evidence provided by non-invasive brain stimulation, however, is inconsistent.
OBJECTIVE/HYPOTHESIS: Here we revisit a major figure discrimination experiment adding a new Kanizsa figure task trying to resolve whether bilateral continuous theta-burst transcranial magnetic stimulation (cTBS) over these regions affects perceptual metacognition. Specifically, we tested whether subjective visibility ratings and/or metacognitive efficiency are lower when cTBS is applied to these two regions in comparison to an active control region.
A within-subjects design including three sessions spaced by one-week intervals was implemented. In each session, every participant was administered bilateral cTBS to either prefrontal, control or parietal cortices. Two concurrent tasks were performed, a real and an illusory figure task, stabilising objective performance with use of an adaptive staircase procedure.
When performing the replicated task, cTBS was found insufficient to disrupt neither visibility ratings nor metacognitive efficiency. However, with use of Kanizsa style illusory figures, cTBS over the dorsolateral prefrontal, but not over the posterior parietal cortex, was observed to significantly diminish metacognitive efficiency.
CONCLUSION(S): Real and illusory figure tasks demonstrated different cTBS effects. A possible explanation is the involvement of the prefrontal cortex in the creation of expectations, which is necessary for efficient metacognition. Failure to replicate previous findings for the real figure task, however, cannot be said to support, conclusively, the notion that these brain regions have a causal role in metacognitive awareness. This inconsistent finding may result from certain limitations of our study, thereby suggesting the need for yet further investigation.
神经影像学和病变研究表明，背外侧前额叶和后顶叶皮层介导视觉元认知意识。然而，非侵入性脑刺激提供的因果证据并不一致。
目的/假设：在这里，我们重新进行了一项主要的数字辨别实验，增加了一个新的 Kanizsa 图形任务，试图确定双侧连续 theta 爆发经颅磁刺激（cTBS）是否会影响这些区域的知觉元认知。具体来说，我们测试了当 cTBS 应用于这些两个区域与主动对照区域相比时，主观可见性评分和/或元认知效率是否较低。
采用包括三个间隔一周的间隔的单盲设计。在每个会话中，每位参与者都接受了双侧 cTBS 刺激，刺激部位分别为前额叶、对照区或顶叶。同时进行了两项任务，一项是真实图形任务，一项是虚幻图形任务，使用自适应阶梯程序稳定客观表现。
在执行重复任务时，发现 cTBS 不足以破坏可见性评分或元认知效率。然而，当使用 Kanizsa 风格的虚幻图形时，发现 cTBS 刺激背外侧前额叶而非顶叶会显著降低元认知效率。
真实和虚幻图形任务显示出不同的 cTBS 效应。一种可能的解释是前额叶皮层参与了期望的形成，这对于有效的元认知是必要的。然而，未能复制以前真实图形任务的发现，并不能确定这些大脑区域在元认知意识中具有因果作用。这种不一致的发现可能是由于我们研究的某些限制造成的，因此需要进一步研究。
